Multi-layer composite body

ABSTRACT

A multi-layer composite body having an at least single-layer carrier layer and a PMMA layer which is carried thereby and which as its main component has standard PMMA, impact-resistant modified PMMA or mixtures thereof, wherein an at least single-layer lacquer layer is printed on to the PMMA layer, and wherein the lacquer layer is printed on to the surface of the PMMA layer, which is remote from the carrier layer.

The invention concerns a multi-layer composite body, in particular a multi-layer film, comprising an at least single-layer carrier layer and a PMMA layer which is carried thereby and which as its main component has standard PMMA, impact-resistant modified PMMA or mixtures thereof, wherein an at least single-layer lacquer layer is printed on to the PMMA layer.

Multi-layer composite bodies are already known, for example for the production of inserts in the sanitary sector by deep drawing (for example EP 781 201).

The object of the invention is to provide a multi-layer composite body and a process for the production thereof, which while involving relatively simple production allows a flexible surface configuration.

According to the invention that is characterised in that the lacquer layer is printed on to the surface of the PMMA layer, which is remote from the carrier layer. In order to achieve different decorations, that lacquer layer can initially be applied over the full surface area and region-wise removal can be effected depending on the respectively desired pattern. That removal operation can be effected either by mechanical engraving or however by means of laser engraving.

It is however also possible, preferably in a screen printing process, for the definitively desired pattern to be printed only in region-wise manner on the PMMA layer right from the outset.

Particularly novel surface configurations can be achieved by the lacquer layer being of a matt-finished nature while the PMMA layer disposed therebetween has a shiny surface. In terms of optical impression that gives a contrast which can be still further increased by colouring of the lacquer layer by means of colour pigments and/or of the PMMA layer.

Further advantages and details of the invention are described more fully with reference to the specific description hereinafter.

FIG. 1 shows a diagrammatic cross-section through a part of an embodiment by way of example of a multi-layer composite body according to the invention,

FIG. 2 shows a plan view of another embodiment of a multi-layer composite body,

FIG. 3 shows a plan view of a further embodiment of a multi-layer composite body, and

FIG. 4 shows possible process combinations for the production of a multi-layer composite body according to the invention in a block flow chart.

The composite body shown in FIG. 1 has a two-layer carrier layer, the two layers being identified by S3 and S4. Those two layers S3 and S4 comprise for example ABS or styrene copolymers, preferably SAN, ASA or PS. They can also comprise polycarbonate. Desirably those layers S3 and S4 are coextruded jointly with the layer S2 described hereinafter. The coloration of the layer S4 is less critical as it is covered by a pure-colour layer S3, covering with inorganic and/or organic pigments. In that way it is also possible to use inexpensive recycled plastic material for the layer S4.

Disposed on the carrier layer S3, S4 is a PMMA layer comprising standard PMMA, impact-resistant modified PMMA or mixtures thereof. Those materials are the main component of the PMMA layer, that is to say at least 80% by weight comprises standard PMMA, impact-resistant modified PMMA or mixtures thereof. In addition that layer S2 may also contain UV-stabilisers or UV-absorbers. In particular that layer S2 can preferably also be provided in covering relationship with inorganic or organic colour pigments. It is however certainly also possible for the PMMA layer to be of a substantially highly transparent nature. Preferably at any event it has a shiny surface.

Now, in accordance with the invention, an additional lacquer layer S1 is applied by printing to that PMMA layer S2, wherein on the finished end product (such as for example FIG. 1), a layer at a greater depth, preferably the layer S2 with its shiny surface, is visible to the viewer (here from above), between the regions of the lacquer layer S1.

A protective film which can be pulled off and which is applied to the uppermost lacquer layer S1 of the composite body can preferably be laminated thereon and after transport can be pulled off prior to actual use, as is indicated by the arrow in FIG. 1.

It is preferably provided that otherwise the uppermost lacquer layer S1 is not covered by a further cover layer. In principle however it is also possible for a clear lacquer layer to be also applied by printing thereover, preferably over the full surface area involved.

The lacquer for the lacquer layer S1 can be a solvent-bearing lacquer, in which respect preferably organic solvents such as for example esthers or ketones can be used as the solvent. It is however also possible to use other lacquer layers depending on the respective situation of use. They include UV-hardening lacquers but in particular also lacquer layers in which a water-dilutable lacquer, preferably acrylate-based, is used.

In accordance with a preferred embodiment of the invention the lacquer layer is of a matt-finished nature, desirably containing a matting agent. That matting agent can comprise for example matting particles which can be of organic or inorganic origin. By way of example matting agent based on silicic acid and to a slight extent of tallow is suitable. The size of those matting agents is preferably larger than the thickness of the lacquer layer S1 and is preferably between 20 μm and 60 μm. The lacquer layer itself is preferably of a thickness of 1 μm to 50 μm, particularly preferably from 2 μm to 20 μm.

Alternatively it is also possible for the lacquer layer to be chemically matted by the addition of constituents which upon hardening of the lacquer result in shrinkage processes in the lacquer matrix.

Furthermore the lacquer layer S1 can be coloured with inorganic and/or organic pigments which either result in an opaque colour layer or however leave the lacquer layer still transparently coloured so that the layer S2 disposed therebeneath still shimmers through. At any event a novel optical effect can be achieved with the matting of the lacquer layer S1 of the shiny surface of the subjacent PMMA layer S2, optionally by additional high-contrast coloration which however is not necessary.

As regards the thicknesses of the layers it is preferable if the overall composite body is of a thickness of between 0.3 mm and 5 mm, particularly preferably between 0.4 mm and 1.5 mm. In that respect the carrier layer S3, S4 makes up the large part of the thickness. The layer S3 can preferably be between 50 μm and 600 μm while the layer S4 is preferably between 500 mm and 2900 mm.

The sizes of the above-specified matting agents (mean size of the cross-sectional dimension) are desirably between 20 μm and 30 μm in the case of fine matting and between 50 μm and 60 μm in the case of coarse matting.

FIG. 2 shows an example of a surface configuration in the case of a multi-layer composite body, in particular a flexible multi-layer film according to the invention. ‘S2’ denotes the shiny surface which is visible between the printed, preferably matted, lacquer layer S1. In the present case this involves a stripe pattern. Other patterns however can also be easily implemented, for example using a screen printing process.

In the embodiment illustrated in FIG. 3 a pattern with extensive circles is applied by printing in the form of a lacquer layer S1 to the PMMA layer S2.

The invention relates not only to a multi-layer composite body but also to a process for the production thereof. According to the invention that process is characterised in that a PMMA layer disposed on a carrier is printed upon with lacquer, forming a lacquer layer.

In that respect it is possible for the lacquer layer firstly to be applied by printing to the PMMA layer substantially over the full area involved and then removed region-wise so that in the removed regions a subjacent layer, preferably the PMMA layer, is exposed. Removal of the lacquer layer can be effected by mechanical engraving or by using lasers (laser engraving). In particular CO₂ lasers and YAG lasers are suitable as the lasers, wherein the CO₂ lasers operate with a wavelength of 20.6 μm and typically involve energies of 10 W to 200 W. The YAG lasers typically operate at 1.064 μm and have an energy of 5 W to 15 W.

It is however possible for the definitive surface pattern of the composite body to be established in the printing step by the PMMA layer being printed upon only in region-wise manner.

In particular the screen printing process is suitable for that purpose. However other processes such as for example intaglio printing, alternate printing and cylinder printing processes, tampon processes or casting processes are certainly conceivable and possible.

As regards production of the carrier layer S3 and S4, that can be coextruded jointly with the PMMA layer (S2).

The multi-layer composite body according to the invention, in particular in the form of a flexible film, can be used as a decorative cover layer, in particular for furniture. Also use for the production of three-dimensional objects, in particular by thermal shaping and/or deep drawing.

FIG. 4 shows an overview of possible process variants.

It will be appreciated that the invention is not limited to the illustrated embodiments, for example the lacquer of the lacquer layer S1 can also be of a highly shiny nature. It can also be arranged over the full surface area over the layer S2. The layer S2 can admittedly preferably be coextruded with the layers S3 and S4. It is however also possible for that layer S2 to be subsequently applied by lamination or printing. 

1. A multi-layer composite body comprising an at least single-layer carrier layer and a PMMA layer which is carried thereby and which as its main component has standard PMMA, impact-resistant modified PMMA or mixtures thereof, wherein an at least single-layer lacquer layer is printed on to the PMMA layer, and wherein the lacquer layer is printed on to the surface of the PMMA layer, which is remote from the carrier layer.
 2. A multi-layer composite body according to claim 1 characterised in that the lacquer of the lacquer layer is a solvent-bearing lacquer, wherein preferably organic solvents such as for example esters or ketones are used as the solvent.
 3. A multi-layer composite body according to claim 2 characterised in that a UV-hardening lacquer is used as the lacquer of the lacquer layer.
 4. A multi-layer composite body according to claim 1 characterised in that a water-dilutable lacquer, preferably based on polyurethane, epoxy resin or acrylate, is used as the lacquer of the lacquer layer.
 5. A multi-layer composite body according to claim 1 characterised in that the lacquer layer is of a thickness of 1 μm to 50 μm, preferably 2 μm to 20 μm.
 6. A multi-layer composite body according to claim 1 characterised in that the lacquer layer covers the subjacent PMMA layer only region-wise, therefore not over the full surface area involved.
 7. A multi-layer composite body according to claim 1 characterised in that the lacquer layer is of a matted nature.
 8. A multi-layer composite body according to claim 7 characterised in that the lacquer of the lacquer layer contains a matting agent.
 9. A multi-layer composite body according to claim 7 characterised in that matting particles are distributed in the lacquer layer.
 10. A multi-layer composite body according to claim 9 characterised in that the matting particles are organic or inorganic.
 11. A multi-layer composite body according to claim 9 characterised in that the size of the matting particles is between 20 μm and 60 μm.
 12. A multi-layer composite body according to claim 7 characterised in that the lacquer layer is chemically matted by the addition of constituents which upon hardening of the lacquer result in shrinkage processes in the lacquer matrix.
 13. A multi-layer composite body according to claim 1 characterised in that the lacquer layer is coloured with at least one of inorganic and organic pigments.
 14. A multi-layer composite body according to claim 1 characterised in that the lacquer layer is opaque.
 15. A multi-layer composite body according to claim 1 characterised in that the lacquer layer is transparent.
 16. A multi-layer composite body according to claim 1 characterised in that the PMMA layer contains one or more of the following components: inorganic or organic colour pigments, UV-stabilisers, UV-absorbers, and matting agents of organic or inorganic origin.
 17. A multi-layer composite body according to claim 1 characterised in that the PMMA layer is of a thickness of 20 μm to 600 μm.
 18. A multi-layer composite body according to claim 1 characterised in that the PMMA layer has a shiny surface.
 19. A multi-layer composite body according to claim 1 characterised in that the carrier layer has at least one layer of ABS or styrene copolymers or polycarbonate.
 20. A multi-layer composite body according to claim 1 characterised in that the side which is towards the PMMA layer has a layer with inorganic or organic colouring pigments.
 21. A multi-layer composite body according to claim 1 characterised in that it is at least of a double-layer configuration and it has a layer which is produced at least partly from recycled plastic material.
 22. A multi-layer composite body according to claim 1 characterised in that the thickness of the overall composite body is between 0.3 mm and 5 mm.
 23. A process for the production of a multi-layer composite body wherein firstly an at least single-layer carrier layer is produced with a PMMA layer which as its main component has standard PMMA, impact-resistant modified PMMA or mixtures thereof, which is then printed upon with lacquer, forming a lacquer layer.
 24. A process for the production of a multi-layer composite body according to claim 23 characterised in that the lacquer layer is first printed substantially over the full surface area on to the PMMA layer and then removed region-wise so that in the removed regions a subjacent layer is exposed.
 25. A process for the production of a multi-layer composite body according to claim 23 characterised in that removal of the lacquer layer is effected by mechanical engraving.
 26. A process for the production of a multi-layer composite body according to claim 23 characterised in that removal of the lacquer layer is effected by laser engraving, wherein preferably CO₂-lasers or YAG-lasers are used as the laser.
 27. A process for the production of a multi-layer composite body according to claim 23 characterised in that the definitive surface pattern of the composite body is established in the printing step by the PMMA layer being printed on only in region-wise manner.
 28. A process for the production of a multi-layer composite body according to claim 23 characterised in that the operation of printing on the lacquer layer is effected using a screen printing process.
 29. A process for the production of a multi-layer composite body according to claim 23 characterised in that it is effected using one of intaglio printing, alternate printing, cylinder printing, tampon printing processes and casting processes.
 30. A process for the production of a multi-layer composite body according to claim 23 characterised in that the layer or layers of the carrier layer and the PMMA layer are coextruded.
 31. A process for the production of a multi-layer composite body according to claim 1 characterised in that a protective film which can be pulled off is applied to the uppermost lacquer layer of the composite body.
 32. Use of the multi-layer composite body according to claim 1 as a decorative cover layer in particular for furniture.
 33. Use of the multi-layer composite body according to claim 1 for the production of a three-dimensional object.
 34. A multi-layer composite body according to claim 1, wherein the multi-layer composite body is a multi-layer film.
 35. A multi-layer composite body according to claim 10, wherein the matting particles are based on silicic acid and optionally tallow.
 36. A multi-layer composite body according to claim 11, wherein the size of the matting particles is greater than thickness of the lacquer layer.
 37. A multi-layer composite body according to claim 16, wherein the inorganic or organic colour pigments important an opaque colour to the PMMA-layer.
 38. A multi-layer composite body according to claim 19, wherein the carrier layer has at least one layer consisting of at least one of a SAN, ASA and PS.
 39. A multi-layer composite body according to claim 20, wherein the inorganic or organic colouring pigments important an opaque colour to said layer.
 40. A multi-layer composite body according to claim 21, wherein said layer which is produced at least partly from recycled plastic material is on the side remote from the PMMA-layer.
 41. A multi-layer composite body according to claim 22, wherein the thickness of the overall composite body is between 0,4 mm and 1,5 mm.
 42. A process for the production of a multi-layer composite body according to claim 24, wherein the subjacent layer which is exposed in the removed regions is the PMMA layer.
 43. A process for the production of a multi-layer composite body according to claim 25, wherein the lacquer layer is hardened.
 44. A process for the production of a multi-layer composite body according to claim 28, wherein the screen printing process is one of a roller screen printing operation and a sheet to sheet screen printing operation.
 45. A process for the production of a multi-layer composite body according to claim 31, wherein said protective film is being laminated on to the upper most lacquer layer.
 46. Use of the multi-layer composite body according to claim 33, wherein said three dimensional object is produced by at least one of thermal shaping and deep drawing.
 47. A multi-layer composite body according to claim 8 characterised in that matting particles are distributed in the lacquer layer.
 48. A multi-layer composite body according to claim 10 characterised in that the size of the matting particles is between 20 μm and 60 μm.
 49. A multi-layer composite body according to claim 8 characterised in that the lacquer layer is chemically matted by the addition of constituents which upon hardening of the lacquer result in shrinkage processes in the lacquer matrix.
 50. A process for the production of a multi-layer composite body according to claim 24 characterised in that removal of the lacquer layer is effected by mechanical engraving.
 51. A process for the production of a multi-layer composite body according to claim 24 characterised in that removal of the lacquer layer is effected by laser engraving, wherein preferably CO₂-lasers or YAG-lasers are used as the laser.
 52. A process for the production of a multi-layer composite body according to claim 26, wherein the lacquer layer is hardened. 